Safety mechanism



Aug. 19, .1947.

I C. L. DENAULT SAFETY MEGHANISM Filed July 14, l1945 ATTORNEY Patented Aug. 19, 1947 UNITED STATES PATENT OFFICE SAFETY MECHANISM Clinton L. Denault, Sharpsville, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 14, 1945, Serial No. 605,051

6 Claims. 1

This invention relates to electrical circuitcontrolling switch devices, and particularly to safety mechanism associated therewith toprevent unauthorized or unintended operation of the switch device.

In many types of apparatus, where it is necessary to operate internal equipment from an operating handle on the outside of the case, it is often necessary to locate and lock the operating equipment in preferred positions. An example of this is the load-center power transformer where an externally operated handle is used to control a disconnect switch inside the transformer case for connecting the transformer to one or more sources of electrical energy as desired, or to disconnect the transformer from its power source.

For this application it has been conventional practice to use a spring-biased stop pin which provides positive engagement within a plurality of holes in a stop plate, depending upon the number of positions in which it is desired to lock the switch device. In accordance with the conventional practice, in order to operate the switch mechanism from one operative position to another, it is necessary to first pull the stop pin against the bias of the spring retaining it in one of these holes until the pin is disengaged from the hole, and then, while holding the pin in the withdrawn position, thus unlocking the switch mechanism to permit operation of the switch by means of a manually operable handle. This procedure is awkward and often difficult. In accordance with the present invention, a mechanism is employed in which the stop pin is always in position to engage within a hole for locking the mechanism when the switch and its operating handle are moved to any one of a plurality of switch operative positions, thus retaining the positive stopping feature of existing equipment while, at the same time, providing for releasing the stop pin and so positioning it that operation of the switch device is possible without manually holding the stop pin while operating the switch device.

One object of the invention is to provide a switch device having a plurality of operative positions with novel means for holding the switch and its operating handle in any desired one of a plurality of operative positions which is eiiicient in operation and simple in construction.

A more specic object of the invention is to provide a switch device having a plurality of operative positions having means for releasably latching the switch in any one of said positions,

which means is adapted to be withdrawn from its latching position to allow free movement of the switch device from one of its operative positions to another, together with the means for automatically adapting the latching means to be released from its withdrawn position so as to again be in a position to latch the switch device upon reaching one of the switch operative positions.

Other objects and advantages of the invention will be apparent from the following description of a preferred embodiment of the invention, reference being had to the accompanying drawing in which:

Figure 1 is a fragmentary elevational View of an electrical apparatus including a switch device in which the circuit-controlling elements are within a housing and an operating handle is located outside of the housing;

Fig. 2 is an enlarged View of a portion of Fig. 1;

Fig. 3 is a vertical sectional view taken along line III-III of Fig. 2;

Fig. 4 is a sectional view similar to that of Fig. 3 with the lock pin in its withdrawn position; and

Fig. 5 is a sectional View taken along the line V--V of Fig. 4.

Referring to Fig. 1 of the drawing, a portion of one wall 2 of a housing is illustrated which is preferably formed of sheet steel. Within the housing there is mounted a pair of stationary Contact tongues 3 and d, each mounted on separate insulators 5 and 6, supported within the housing on transversely extending spaced channel supports 'I and 8. A stop plate I I is mounted by means of screws I2 to the wall portion 2 of the housing through which extends a shaft I3, supported in suitable bearings in the stop plate and carrying a switch blade I4 on an insulated portion at the inner end of the shaft I3. The switch blade I is adapted to engage either of the contact tongues 3 or ll or to be held in its illustrated vertical disconnected position. The switch blade Ill may be of a type having spaced sides secured against relative operation at their outer ends by bolt i6 so that when the blade is pivotally moved about the axis of the shaft I3 to engage one of the contact tongues 3 and 4, the contact tongue will be received between the sides of the blade I4, with theconnecting bolt I6, received in a notch I'I, provided in the outer end of each contact tongue. The particular structure of the switch contact elements forms no part of the present invention and, therefore, need not be further described.

An operating handle I8 is attached to the shaft I3 on the outside of the housing wall 2, and may be provided with a sleeve I9 extending about the outer end of the shaft I3 and through an opening 2I in the stop plate II and attached by any suitable means, such as a pin 22, to operate the shaft I3 and the switch blade I4.

A plurality of holes 23 are provided in the stop plate II and are arranged about the axis of the shaft I3 in spaced relation to permit the outer end 24 of a stop pin 25 to engage within one of these holes when the switch blade I4 and operating handle I8 are in any one of the three illustrated operative positions of the switch device. The stop pin 25 is provided with a stop pin cam 26 a short distance back from the outer end 24 of the pin. As shown in Figs. 3 and 4, a spring 2'1 is shown between the cam 26 and ther inner surface of the handle I8 to -bias the stop pin 25 in a direction to cause the end 24 of the pin to enter and engage within one of the holes 23 when the handle is in position to bring the pin opposite one of these holes. When the stop pin 25 is in its latching position, as shown in Figs. l, 2 and 3, the stop holdout pin 28 is in a horizontal position between two holdout bosses 29 extending outwardly from the surface of the operating handle I8, and the inner end 24 of the stop pin 25 is engaged within the hole 23.

When it is desired to operate the switch device from a switch operative position in which it is latched, the operator seizes the handle or knob 3I of the stop-pin 25 and withdraws the pin to disengage the end 24 from the hole 23 in the stop plate I I, turning the stop-pin 25 through approximately 900 after withdrawing it, bringing the stop holdout pin 28 into a substantially vertical position to engage the outer ends of the holdout bosses `29, thus holding the spring 2T under tension as shown in Fig. 4 so that the operator may release hold of the handle 3| and operate the switch mechanism by means of the operating handle I8.

When the stop-pin 25 is in its .withdrawn position, as shown in Fig. 4, so that the stop holdout pin 28 is in a substantially vertical position, the cam 26 is also in a substantially vertical position. As the handle I8 is moved from one switch operative position to another, starting with the stoppin 25 in the withdrawn position shown in Figs. 4 and 5, the stop pin cam 2B will engage one of the cam return bosses 32, extending outwardly from the stop plate II, so as to rotate the stop pin 25 through substantially 90 and disengage the stop holdout pin 28 from engagement with the outer ends of the holdout bosses 29 allowing the spring 21 to move the stop pin 25 inwardly to cause engagement between its inner end 24 with the outer wall of the stop plate II, thus adapting the mechanism so that when the operating handle I8 and the switch blade I4 are moved to the next operative position of the device, the stop pin 25 will be operated by the spring 2'I causing engagement of the inner end 24 of the stop pin within the opening 23 in the stop plate corresponding to that operative position of the switch operating mechanism.

In the illustrated embodiment of the invention, three operative positions of the switch device are shown and, therefore, three holes 23 are provided in the stop plate II corresponding to these three operative position It will be appreciated that in diiTerent switch devices different numbers of operative positions may be employed and a correspondingly dii-ferent number oi holes 23 will, therefore, be provided in the stop plate with the required number of cam return bosses 32 positioned therebetween for moving the stop-pin from its released position upon movement of the operating handle I8 from one switch operative position to another switch operative position. Thus, the stop-pin 25 will be adapted to be operated by the spring 21 to the locking position shown in Fig. 3, in which the inner end of the pin 25 is within one of the holes 23 in the stop plate II to retain the handle I8 and the switch mechanism operated thereby in locked position until the stoppin is again manually withdrawn from this position as above described.

It will be understood by those skilled in the art that modifications may be made in the details of the structure illustrated and described without departing from the spirit of my invention, and I do not wish to be otherwise limited than by the scope of the appended claims.

I Claim as my invention:

1. In a circuit controlling device, a manually operable switch actuating member having a plurality of switch operative positions, latch means for automatically locking said switch actuating member in any one of said plurality of switch operative positions, said latching means comprising a stop plate over which the switch actuating member is adapted to move, a stop-pin extending through an opening in said actuating member and a plurality of holes in said stop plate corresponding to the several operative positions of said switch actuating member and adapted to receive the stop-pin, and means for biasing said stop-pin to engage within one of said holes when the switch actuating member is in one of said switch operative positions to prevent movement of said switch actuating member from a switch operative position without first withdrawing said stoppin from said hole, means for retaining said stoppin out of engagement with one of said holes while the switch actuating member is in one switch operative position and means responsive to the movement of the switch actuating member to another switch operative position for releasing said stop-pin from its withdrawn position to adapt it to engage within any one of said holes upon movement of said switch actuating member to the corresponding one of said switch operative positions.

2, In a circuit controlling device, a manually operable switch actuating member having a plurality of switch operative positions, latch means for automatically locking said switch actuating member in any one of said plurality of switch positions, said latchingy means comprising a stop plate over which the actuating member is adapted to move, a stop-pin extending through an opening in said switch actuating member and a plurality of holes in said stop plate corresponding to the several switch operative positions of said switch actuating member and adapted to receive the stop-pin, and means for biasing said stop-pin to engage within said holes when the switch actuating member is in one of said switch operative positions to prevent movement of said switch actuating member from a switch operative position without rst withdrawing said stop-pin from said hole, said stop-pin having a stop holdout pin therethrough adjacent its outer end and extending beyond the shank of stop-pin, a stop-pin cam adjacent the inner end of the stop-pin, holdout bosses on the switch actuating member for receiving the stop holdout pin in a. predetermined position of the stop-pin to withhold the stop-pin from engagement within one oi said holes, and cam return bosses on said stop plate adapted to be engaged by said stop-pin cam when the switch actuating member is moved from one switch operative position to another for rotating the stop-pin to a position to release the stop holdout pin from the holdout bosses and permit the stoppin to engage within one of said holes when the switch actuating member is moved to one of said switch operable positions.

3. In a circuit controlling device, a manually operable switch actuating member having a plurality of switch -operative positions, locking means operative upon movement of the switch actuating` member to any one of said plurality of switch operative positions for locking said switch actuating member in said position, said locking means being manually releasable from its locking position, means operative upon withdrawal of the locking means from its locking position and movement of the locking means to a predetermined released position for withholding said locking means from its locking position, and means operative upon movement of said switch actuating member from one switch operative position to another switch operative position while said locking means is in said predetermined released position for effecting movement of said locking means from its released position for conditioning said locking means for locking said switch actuating member upon movement thereof to one of said switch operative positions.

4. Switch operating mechanism comprising a manually operable switch actuating member having a plurality of switch operative positions, latch means for automatically locking said switch actuating member in any one of said plurality of switch operative positions, said latching means comprising a stop plate over which the actuating member is adapted to move, a stop-pin extending through an opening in said switch actuating member and means for latching said stop-pin to said stop plate when the switch actuating member is in one of said operative positions to prevent movement of said switch actuating member from a switch operative position without rst releasing said stop-pin from latching engagement with said stop plate, means for withdrawing said stop-pin from latching engagement with said stop plate and for retaining said stop-pin out of latching engagement with said stop-plate while the switch actuating member is in a switch operative position, and means responsive to the movement of the switch actuating member to another switch operative position for releasing said stop-pin from its withdrawn position to adapt it to again effect latching engagement withY said stop plate upon movement of said switch actuating member to one of said switch operative positions.

5. Switch operating mechanism comprising a housing, a manually operable switch operating handle positioned outside of said housing and pivotally mounted with respect thereto, said operating handle having a plurality of switch operative positions, locking means for automatically locking said switch operating handle in any one of said plurality of operative positions, said locking means comprising a stop plate attached to an outer side of the housing wall, a stop-pin extending through an opening in said operating handle and a plurality of holes in said stop plate corresponding to the several operative positions of said actuating means and adapted to receive the stop-pin, and means for biasing said stop-pin to engage within said holes in the stop plate when the switch operating handle is in one of said switch operative positions to lock the switch operating handle against movement from a switch operative po-sition without rst withdrawing said stop-pin from said hole, said stop-pin having a stop holdout pin therethrough extending beyond the shank of the sto-p-pin, a stop-pin cam on said stop-pin, holdout bosses on the switch operating handle for receiving the stop holdout pin in a predetermined position of the stop-pin to withhold the stop-pin from engagement with one of said holes, and cam return bosses on said stop plate for engaging the stop-pin cam for releasing the stop holdout pin from engagement with the holdout bosses when the switch operating handle is moved from one switch operative position to another switch operative position to permit the stop-pin to engage within one of said holes when the switch actuating member is moved to one of said switch operative positions,

6. Switch operating mechanism comprising a housing, a 'manually operable switch actuating member positioned outside of said housing and having a plurality of switch operative positions, locking means operative upon movement of the switch actuating member to any one of said plurality of switch operative positions for locking said switch actuating member in said position, said locking means including a stop plate attached to a wall of the housing and a stop-pin carried by said actuating member, said stop plate having a plurality of holes therein corresponding to the several operative positions of said switch actuating member and adapted to receive the stop-pin in a locking position to engage within one of said holes when the switch actuating member is in one of said switch operative positions, said stop-pin being manually releasable from its locking position, means operative upon withdrawal of the stop-pin from its locking position and movement of the stop-pin to a predetermined released position for withholding said stop-pin from its locking position, and means operative upon movement of said switch actuating member from one switch operative position to another switch operative position while said stop-pin is in said predetermined released position for effecting movement of said stop-pin from its released position for conditioning said stop-pin for locking said switch actuating member upon movement thereof to one of said switch operative positions.

CLINTON L. DENAULT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,299,257 Stevens Apr. 1, 1919 1,008,000 Whittingham Nov. 7, 1911 1,012,525 Cullen Dec. 19, 1911 

